Contacts posing risks of disease introduction in swine breeding herds in Quebec, Canada: Is the frequency of contacts associated with biosecurity measures?

The introduction of pathogens into swine breeding herds can occur through a variety of contacts involving people, animals, vehicle or various supplies. Appropriate biosecurity is critical to mitigate these risks. A retrospective study was conducted to describe contacts with swine breeding sites over a one-month period and to evaluate their association with biosecurity measures and site characteristics. As part of a larger project, sites which had a recent porcine reproductive and respiratory syndrome virus introduction were selected. A questionnaire, logbooks and pig traceability system were used for collecting data relative to persons or supplies entering the breeding unit, live pig transportation, service vehicles, other animal species, neighboring pig sites and manure spreading around the site. The 84 sites investigated had a median sow inventory of 675. A median of 4 farm staff and 2 visitors entered the breeding unit at least once over the one-month period. A total of 73 sites (87%) received visitor(s), mostly from maintenance and technical services. All sites received at least 3 supply deliveries (median of 8) including semen (99% of sites), small material and/or drugs (98% of sites), bags (87% of sites), and/or equipment (61% of sites). Live pig movements were observed in all sites, with a median number of 5 truck entries on the site or exits from the site. For feed mill, rendering and propane trucks, at least one entry was noted in ≥ 61% of sites. For all service vehicle categories except feed mill and manure vacuum trucks, a single service provider was involved in each site. Dogs and cats were banned from all sites, but wild birds were observed in 8% of sites. Manure spreading within a 100 m radius of pig units was noted in 10% of the sites. With a few exceptions, biosecurity measures were not associated with the frequency of contacts. A 100-sow increase in sow inventory was associated with an increase of 0.34 in the cumulated number of staff entering the breeding unit, of 0.30 in the number of visitors and of 0.19 in the number of live pig movements. Live pig movements were also positively associated with vertically integrated farrow-to-wean (vs. independent farrow-to-wean) production and time interval of 4 weeks or more between farrowing (vs. less than 4). Considering the variety and frequency of contacts observed, biosecurity should be meticulously applied in all breeding herds to prevent endemic and exotic disease introduction.

Sorption kinetics of chlortetracyline and tylosin on sandy loam and heavy clay soils.

Antibiotics may appear in the environment when manure, sewage sludge, and other organic amendments are added to soils. There is concern that the presence of antibiotics in soils may lead to the development of antibiotic-resistant bacteria which may spread to the rest of the environment. This paper aims at evaluating the sorption kinetics of two antibiotics frequently used in pig production. The results indicate that sorption of chlortetracycline (CTC) and tylosin (TYL) in sandy loam and clay occurs very fast. More than 95% of the CTC adsorption is completed within 10 min on both soils and of TYL within 3 h. These results suggest that 24-h soil and antibiotic solution mixtures is enough for sorption studies. Also, there is less likelihood that these antibiotics will leach through soil and appear in the ground water since their sorption on soils is very high unless they are carried by soil particles through preferential flow. There was also no effect of soil sterilization on sorption kinetics of these antibiotics thus suggesting that there is minimal probability of the antibiotics degrading by microorganisms during 24- to 48-h adsorption studies.

Isolation of variants resistant to methylglyoxal bis(guanylhydrazone) from adenovirus-transformed rat cells.

It is presumed that proteins encoded by viral oncogenes interact with proteins encoded by cellular genes to bring about the transformed phenotype. To demonstrate the existence of such cellular genes we attempted to isolate mutants with a nontransformed phenotype from an adenovirus-transformed rat cell line (F4) which contains multiple copies of the transforming E1 region. F4 cells were mutagenized with ethyl methanesulfonate and variants resistant to the anticancer drug methylglyoxal bis(guanylhydrazone) were selected. The proportion of such variants was about one in 10(6) and increased 5-fold after mutagenesis. Two variant clones (G1 and G2) were isolated and characterized: they were 5-fold more resistant to methylglyoxal bis(guanylhydrazone); they had a stable phenotype; they showed decreased drug uptake; they had a reduced ability to grow in soft agar, low serum, and nude mice; there was no detectable change in the restriction pattern of integrated viral genes or in the expression of the E1a and E1b proteins. These properties suggest that selection for methylglyoxal bis(guanylhydrazone) resistance may result in the isolation of variants with phenotypic characteristics of nontransformed cells. It was likely that these variants were altered in a cellular function required for the maintenance of the transformed phenotype.

The 2014 liver ultrasound tracking benchmark.

The Challenge on Liver Ultrasound Tracking (CLUST) was held in conjunction with the MICCAI 2014 conference to enable direct comparison of tracking methods for this application. This paper reports the outcome of this challenge, including setup, methods, results and experiences. The database included 54 2D and 3D sequences of the liver of healthy volunteers and tumor patients under free breathing. Participants had to provide the tracking results of 90% of the data (test set) for pre-defined point-landmarks (healthy volunteers) or for tumor segmentations (patient data). In this paper we compare the best six methods which participated in the challenge. Quantitative evaluation was performed by the organizers with respect to manual annotations. Results of all methods showed a mean tracking error ranging between 1.4 mm and 2.1 mm for 2D points, and between 2.6 mm and 4.6 mm for 3D points. Fusing all automatic results by considering the median tracking results, improved the mean error to 1.2 mm (2D) and 2.5 mm (3D). For all methods, the performance is still not comparable to human inter-rater variability, with a mean tracking error of 0.5-0.6 mm (2D) and 1.2-1.8 mm (3D). The segmentation task was fulfilled only by one participant, resulting in a Dice coefficient ranging from 76.7% to 92.3%. The CLUST database continues to be available and the online leader-board will be updated as an ongoing challenge.

Evaluation of dermal and respiratory chloroform exposure in humans.

Chloroform is a known contaminant of chlorinated drinking water and of swimming pool water disinfected with chlorine or one of its derivatives. Few data exist regarding the importance of dermal and inhalation exposure routes to the chloroform body burden resulting from domestic and recreational use of chlorinated water. In our experimental study involving 11 male swimmers, we quantified the body burden resulting from exposure to various concentrations of chloroform in water and air of an indoor swimming pool, during a daily 55-min exercise period. From the first to the sixth exercise period, CHCl3 mean concentration in water was increased from 159 micrograms/l to 553 micrograms/l. Corresponding mean air CHCl3 level ranged from 597 ppb to 1630 ppb. To dissociate the dermal exposure route from that of inhalation, swimmers used scuba tanks during an additional exercise period. Chloroform concentrations were measured in alveolar air before and after each exercise period, as well as after 35 min of physical activity. Chloroform levels in water and air were measured every 10 min. We examined the relationship between alveolar air concentration (a measure of body burden) at 35 and 55 min and environmental chloroform concentrations by using multiple regression models. The natural logarithm of alveolar air concentration was strongly correlated with aqueous chloroform concentration both at 35 (p2 < 0.001, r2 = 0.75) and 55 min (p < 0.001, r2 = 0.86). The relationship with air concentrations was also statistically significant (35 min: p < 0.001, r2 = 0.58, 55 min: p < 0.001, r2 = 0.63).(ABSTRACT TRUNCATED AT 250 WORDS)

Reducing work disability associated with rheumatoid arthritis: identification of additional risk factors and persons likely to benefit from intervention.

OBJECTIVE: To study additional risk factors for rheumatoid arthritis (RA)-related work disability and to identify the groups of individuals at high risk and the potentially modifiable factors which place them at risk. METHODS: A cross-sectional mail survey was conducted among 469 adults with RA. Work disability was defined as unemployment due to RA. A broad range of explanatory factors was examined, including sociodemographic, health, work, support given by others, and commuting difficulty. Employed and work-disabled subjects were compared by t-test and chi-square. Attributable fractions were calculated to assess the predictive value of factors. A recursive partitioning procedure identified individuals at varying risks for work disability, and their characteristics were defined. RESULTS: The risk factors joint pain and functional status, commuting difficulty, physical demands of the job, and disease duration were important predictors of work disability in both the attributable fraction and recursive partitioning analytic models. Having a professional or administrative job was protective, provided the salary earned was not low. Younger individuals with RA of shorter duration were placed at high risk by potentially modifiable factors. While older persons with RA of long duration were at high risk, modifiable factors could not be identified. CONCLUSION: Commuting difficulty, a previously overlooked factor, is an important predictor of RA work disability. Younger individuals with RA of relatively short duration can be placed at high risk by potentially modifiable factors including commuting difficulty, physically demanding jobs, greater joint pain and poor functional status, and nonprofessional/non-administrative jobs.

The costs of rheumatoid arthritis.

The economic costs associated with rheumatoid arthritis (RA), a chronic, systemic, inflammatory disorder that affects many joints, are high, approximating those of coronary heart disease. The estimated prevalence of RA in the US is 0.9%. Incidence increases with age, and is highest among women in the fourth to sixth decades of life. The primary impact of RA is due to the significant morbidity associated with this disease. Mortality is increased among a poorly defined subgroup of RA patients. The average level of disability among RA patients is moderate, but 6.5 to 12% of patients are severely disabled. Between one- and two-thirds of previously employed patients have a reduced work capacity. Treatment primarily involves the use of nonsteroidal anti-inflammatory drugs and disease modifying antirheumatic drugs. Rehabilitation measures and orthopaedic surgery are also used. Total annual direct costs of RA (total charges) have been calculated to be $US5275 and $US6099 (1991 dollars) per patient. Lifetime medical care charges were estimated at $US12,578 per patient (1991 dollars). The direct costs of RA are substantial, but indirect costs have been calculated to be much higher because of extensive morbidity. The difference between the direct and indirect costs of RA is decreasing because salary increases have not kept pace with rising healthcare costs. The latter are increasing rapidly in RA because of the use of new technology, surgical procedures, and the greater use of drugs with frequent monitoring requirements and significant toxicity. Because intangible costs such as pain form a substantial part of the overall costs of RA but are difficult to evaluate, cost estimates inevitably underestimate the impact of the disease on individuals and society.

Epidemiology of Streptococcus suis serotype 5 infection in a pig herd with and without clinical disease.

The aim of this study was to describe the transmission and the kinetics of the infection caused by Streptococcus suis serotype 5 in a multisite farrow-to-finish pig herd. Most sows carried S. suis serotype 5 in their vaginal tract, but not in their nasal cavities, as demonstrated by immunomagnetic separation (IMS) technique. Their offspring became infected during farrowing, confirming vertical transmission. During the first 4 weeks of life, a low number of piglets were carriers of S. suis serotype 5 in their nasal cavities. However, when clinical signs appeared, the carrier rate significantly increased, suggesting that isolation from nasal cavities is a better indication of active transmission than of a carrier state. Clinical cases were present in animals between 4 and 8 weeks of age, when maternal antibodies were at their lowest level. Up to six different genotypes of the same serotype could be identified by random amplified polymorphic DNA; however, a single clone was responsible for all clinical cases studied. This clone could only be isolated from a single sow, indicating that its prevalence in breeding animals was low. Interestingly, 1 year later, clinical disease associated with S. suis serotype 5 spontaneously disappeared. At that time, the genotype responsible for the clinical signs was not detected in the herd and the levels of antibodies in sows and maternal antibodies in piglets were not higher than those of the previous year.

Detection of antibodies against Streptococcus suis capsular type 2 using a purified capsular polysaccharide antigen-based indirect ELISA.

In the present study a purified capsular polysaccharide antigen-based indirect ELISA (CPS-ELISA) to detect antibodies against Streptococcus suis capsular type 2 was developed and compared with a whole cell antigen-based ELISA (WCA-ELISA). The WCA-ELISA presented a very low specificity when rabbit antisera to other capsular types were tested. Most of these cross-reactions were due to common proteins. The standardized CPS-ELISA gave satisfactory results using a concentration of 0.1 micrograms/well; most cross-reactions decreased significantly, with some exceptions, such as those shared by capsular types 1/2, 12 and 17. These cross-reactions were mainly due to common epitopes present in the capsule, as shown by immunoblotting. In a second experiment, the CPS-ELISA was used to detect antibodies in experimentally infected piglets. Despite the fact that capsular type 2 S. suis could be reisolated from all infected animals during and/or after the trial, antibody titers against a second infection. Sera from piglets experimentally infected were completely protected against a second infection. Sera from piglets experimentally infected with S. suis capsular types 1/2 or 12 presented cross-reactions at low dilutions, confirming data previously obtained with rabbit sera. Finally, sera of animals from herds with clinical signs associated with S. suis capsular type 2 did not present titers significantly different from those of disease free herds. From our results we concluded that the CPS-ELISA developed in this study can not be used as a diagnostic tool to identify infected animals.

Air quality monitoring during indoor Monster Truck and car demolition shows.

This article describes the results of air quality monitoring in an indoor ice skating rink during three Monster Truck and car demolition exhibitions, and the public health study that was carried out. The exposure of the people present to carbon monoxide and nitrogen dioxide was continuously monitored in order to determine the time-weighted average concentrations and the maximum peaks. Nitrogen dioxide concentrations were generally under the limit of detection of the device (0.5 ppm). However, carbon monoxide levels exceeded standards for workers. Maximum time-weighted average concentrations during the exhibitions were 100 parts per million with several peaks exceeding 200 parts per million (maximum value: 1600 parts per million). Recommendations were made and during a subsequent event, the carbon monoxide concentrations were reduced to protect health. Indoor exhibitions of motorized vehicles generate significant amounts of combustion gases, which can be a health hazard. There must be sufficient ventilation and the carbon monoxide and nitrogen dioxide concentrations must be monitored. In addition, the motors of the most polluting vehicles should be adjusted before the events in order to limit the emission of combustion products. If these steps are not met, the events should be held outdoors.

Evaluation of the health risk associated with exposure to chloroform in indoor swimming pools.

The exposure of swimmers to chloroform (CHCl3) was investigated in indoor swimming pools of the Quebec City region along with the associated carcinogenic risk. Six training sessions involving 52 competition swimmers (11 to 20 yr old) were conducted in 3 different pools, while 12 adult leisure swimmers attended 5 sessions, each held in a different pool. For each session, water and ambient air CHCl3 concentrations were measured and CHCl3 levels in alveolar air samples (CHCl3 ALV) collected from swimmers prior to entering the swimming pool premises and after 15, 35, and 60 min of swimming. Mean water concentrations varied from 18 microg/L to 80 microg/L, while those in air ranged from 78 microg/m3 to 329 microg/m3. Multiple linear regression analyses revealed that CHCl3 ALV values in competition swimmers were strongly correlated to ambient air and water levels, and to a lesser degree to the intensity of training. Only ambient air concentration was positively correlated to CHCl3 ALV in the leisure group. Concentrations of CHCl3 metabolites bound to hepatic and renal macromolecules, estimated using a physiologically based pharmacokinetic (PBPK) model, were 1.6 and 1.9 times higher for the competition swimmers than for the leisure swimmers, respectively. The highest hepatic concentration predicted in competition swimmers, 0.22 microg CHCl3 equivalents/kg of tissue, was at least 10,000 times lower than the smallest no observed effect level for liver tumors in animals. Data indicate that the safety margin is therefore very large, for competitive swimmers as well as for leisure swimmers.

The evaluation of postmortem ocular fluid analysis as a diagnostic aid in sows.

This study was undertaken to evaluate the diagnostic usefulness of postmortem ocular fluid analysis in estimating the antemortem status of various serochemical constituents. Chemical values of serum and aqueous and vitreous humors were compared following different procedures. A blood sample and the 2 eyes were collected from each of 100 sows at a nearby abattoir. The results obtained from immediate centrifugation of ocular fluids after sampling were compared with those samples in which centrifugation was delayed by 2 hours. Two different postmortem intervals were used for sampling ocular fluids, 2 and 24 hours. Concentrations of urea, calcium, phosphorus, potassium, sodium, and chloride were determined from serum and humors. Delayed centrifugation did not affect chemical values of ocular fluids nor the relationships between serum and humors. Phosphorus and potassium values increased significantly with the postmortem interval in both aqueous and vitreous humors. The relationships between chemical values of ocular fluids and serum were determined using simple linear regression. There was a poor correlation between ocular fluid and serum values for all electrolytes; a significant correlation was found only for urea concentrations in both humors.

Wood-burning appliances and indoor air quality.

Wood heating represents an interesting economic alternative to electrical or heating oil and gas systems. However, many people are concerned about poor indoor air quality in homes equipped with wood-burning appliances. We conducted a study in the Quebec City region (Canada) to verify the extent of indoor air contamination, and to examine the frequency of respiratory symptoms and illnesses among occupants of wood-heated homes. One child attending primary school (median = 8 years old; range = 5-14 years old) and an adult (median = 37 years old; range = 23-52 years old) were recruited in each eligible house. Eligible houses were without known sources of combustion products (smokers, attached garage, oil or gas furnace, gas stove, etc.) except for wood-burning appliance. Out of the 89 houses included in the study, 59 had wood-burning appliances. Formaldehyde, nitrogen dioxide, respirable particles (PM10) and carbon monoxide were measured in a sub-set of 49 houses (41 with a wood-burning appliance and 8 without). The frequency of respiratory symptoms and diseases among participants were documented using a daily symptom diary. Concentrations of contaminants were low in most houses, both with or without a wood-burning appliance. Globally, there was no consistent relationship between the presence of a wood-burning appliance and respiratory morbidity in residents. Nevertheless, residents who mentioned being exposed to fumes emitted by such an appliance reported more respiratory illnesses and symptoms. The presence of animals or molds, and keeping windows closed most of the time in winter were other factors associated with respiratory problems. We conclude that wood burning appears to be a respiratory health risk for occupants if the appliance is not maintained and used properly.

Rapid, sensitive, and noninvasive sampling technique for determination of chloroform in alveolar breath.

A sampling technique for the determination of chloroform in alveolar breath is presented. Subjects exhale in a homemade device for collection of the alveolar fraction. The collected sample is transferred to a partially evacuated headspace vial and subsequently analyzed by capillary gas chromatography using electron-capture detection. Concentrations greater than 50 micrograms/m3 can readily be detected. Good correlation observed between chloroform levels in alveolar breath and plasma validates the sampling technique.

A dynamic two-dimensional system for measuring volatile organic compound volatilization and movement in soils.

There is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two-dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real-time concentration measurement. Gas distribution in the soil profile was sampled with gas-tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed-furrow system. A 5-h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3-bromo-1-propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br-) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration-time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models.

Gas-phase sorption-desorption of propargyl bromide and 1,3-dichloropropene on plastic materials.

The goal of this research was to provide information for choosing appropriate materials for studying gas-phase concentrations of propargyl bromide (3BP) and 1,3-dichloropropene (1,3-D) in laboratory experiments. Several materials were tested and found to sorb both gas-phase chemicals in the following order: stainless steel (SS) < Teflon polytetrafluoroethylene (PTFE-FEP) approximately flexible polyvinyl chloride (PVC) approximately acrylic < low-density polyethylene (PE) < vinyl approximately silicone < polyurethane foam (PUF). Sorption of SS was insignificant and PUF sorbed all the fumigant that was applied. For the other materials, linear sorption coefficients (Kd) for 3BP ranged from 3.0 cm3 g(-1) for PVC to 215 cm3 g(-1) for silicone. Freundlich sorption coefficients for 1,3-D ranged from 11.5 to 371 cm3 g(-1). First-order desorption rate constants in an open system ranged from 0.05 to 1.38 h(-1) for 3BP and from 0.07 to 1.73 h(-1) for 1,3-D. In a closed system, less than 2% of sorbed fumigant desorbed from vinyl while up to 99% desorbed from PVC within 24 h when equilibrated at the highest headspace concentration. Sorption of both fumigants was linearly related to the square root of time except for vinyl and silicone. This may indicate non-fickian diffusion of fumigant into the polymer matrix. Vinyl, silicone, PE, and PUF should be avoided for quantitative study of organic gases, except possibly as a trapping medium. Use of PTFE, PVC, and acrylic may require correction for sorption-desorption and diffusion.

Physiological responses to treadmill exercise and ambient temperature in normal and malignant hyperthermia susceptible pigs.

Ten susceptible and ten resistant pigs to malignant hyperthermia were used to observe the effects of exercise and ambient temperature on selected physiological parameters. Pigs were submitted to a ten minute exercise on a treadmill operating at a speed of 1.8 km/h and inclined to 11 degrees. Exercise in the first group was at an ambient temperature of 14 degrees C, and in the second at 29 degrees C. The right carotid artery was previously cannulated for blood pressure measurements and for repeated blood sampling during exercise. Arterial pressure, heart rate, rectal and cutaneous temperatures were recorded. Levels of cortisol, creatine kinase and its isoenzymes were measured. At 14 degrees C, exercise caused some physiological adjustments in susceptible animals; heart rate, skin temperature and cortisol levels increased (P less than 0.05). In resistant pigs, only the heart rate was elevated significantly following exertional stress at 14 degrees C. Exercise at 29 degrees C produced severe stress and marked physiological changes: heart rate, rectal and skin temperatures and cortisol levels increased significantly in both susceptible and resistant swine. At 29 degrees C, susceptible pigs also had higher levels of serum cortisol, total creatine kinase and MM isoenzyme (P less than 0.05) compared to resistant pigs. The results indicate that, following exertional or thermal stress, susceptible pigs undergo more extensive physiological changes than do resistant pigs. Similar levels of stress prior to slaughter may trigger physiological changes which in the susceptible pigs would likely result in pale, soft exudative myopathy.

A prospective study of sow mortality in breeding herds.

This investigation was conducted to study the incidence and the causes of sow mortality in breeding herds. Data were obtained from 24 swine breeding herds with an average inventory of 3755 sows and served gilts for the total sample. Producers were involved for 12 consecutive months and agreed to submit to the diagnostic laboratory every dead or moribund sow and served gilt. The average herd death rate was 3.3% +/- 0.5 (SEM), but varied considerably among herds, ranging from 0% to 9.2%. A total of 137 sows and mated gilts died during the year, and these females had produced an average of 4.2 litters +/- 0.2 (SEM). The number of deaths was significantly higher during the months of July, August and October. The peripartum period appeared to be when sows were most at risk, with 42% of all deaths occurring during this short period of the reproductive cycle. The three major causes of death were heart failure (31.4%), torsions and accidents of abdominal organs (15.3%) and cystitis-pyelonephritis (8.0%). Other causes included endometritis (6.6%), uterine prolapses (6.6%), pneumonia (3.6%), gastric ulcers (3.6%), downer sow syndrome (2.2%), miscellaneous (8.0%) and unknown (14.6%).

Survey of management and housing in farrowing quarters among independent and integrated swine farms in Québec.

Forty-eight randomly selected owner-operated swine breeding farms (independent farms) and 38 belonging to 5 integrated organizations specializing in swine production chosen from the largest in the province of Québec (integrated farms) were separately described regarding their general characteristics, sow feeding, management practises, and housing features in farrowing quarters. The parallel description of these 2 groups of farms aids in understanding what is done in the field. It also provides insight into potential differences between independent and integrated farms. Generally speaking, production tended to be more specialized and concentrated in integrated organizations. Specifically, more new practises seemed to have been adopted on the integrated farms, and their stockpersons seemed to have a more proactive style of management in farrowing quarters. Increased size of operations, proximity of information sources, profits yielded by new practises, and ease of implementation are discussed as explanations for this higher rate of adoption of new techniques among the organizations. These differences between the independent farms and the integrated organizations appeared to be all related to basic differences in their respective sizes. Although some differences were observed within, as well as between, each organization, many similarities were found across the majority of farms within each organization, thus supporting the existence of policies specific to each organization. Although these findings have to be confirmed before being generalized, they tend to suggest that independent swine farms and integrated organizations should be considered differently.

Antibody response to an autogenous vaccine and serologic profile for Streptococcus suis capsular type 1/2.

An autogenous vaccine was developed, using sonicated bacteria, with a strain of Streptococcus suis capsular type 1/2. The objectives of this study were to evaluate the antibody response following vaccination and to assess the changes in antibody levels in pigs from a herd showing clinical signs of S. suis capsular type 1/2 infection in 6- to 8-week-old pigs. An enzyme-linked immunosorbent assay using the vaccine antigen was standardized. Results from a preliminary study involving 2 control and 4 vaccinated 4-week-old pigs indicated that all vaccinated pigs produced antibodies against 2 proteins of 34 and 43 kDa, respectively, and, in 3 out of 4 vaccinated pigs, against the 117-kDa muramidase-released protein. For the serologic profile, groups of 30 pigs from the infected herd were blood sampled at 2, 4, 6, 8, and 10 weeks of age. The lowest antibody level was observed between weeks 6 and 8, presumably corresponding to a decrease in maternal immunity. A marked increase was seen at 10 weeks of age, shortly after the onset of clinical signs in the herd. For the vaccination field trial, newly weaned, one-week-old piglets were divided into 2 groups of 200 piglets each (control and vaccinated); blood samples were collected from 36 piglets in each group at 2-week intervals for 12 weeks. A significant increase (P < 0.05) in antibody response was observed 4 weeks following vaccination and the level of antibodies stayed high until the end of the experiment. In the control group, the increase was only observed at 13 weeks of age, probably in response to a natural infection. The response to the vaccine varied considerably among pigs and was attributed, in part, to the levels of maternal antibodies at the time of vaccination. No outbreak of S. suis was observed in the control or vaccinated groups, so the protection conferred by the vaccine could not be evaluated.